This application claims priority from Japanese patent application Serial no. 2001-109471 filed Apr. 9, 2001, the contents of which are incorporated by reference herein.
1. Field of the Invention
The present invention relates generally to a method and apparatus for controlling a rotary press in a power failure, and more specifically to a method and apparatus for controlling, in a power failure, a so-called shaftless rotary press that produces printing impressions on paper by separately driving printing sections and folding sections with independent drive units.
2. Description of the Related Art
Conventional types of rotary presses accomplish printing operation by driving the entire rotary press with an integrated drive-source assembly that connects a plurality of drive units (main motors) provided on printing sections, folding sections and other components comprising the rotary press via a drive transmission shaft (main shaft) and a clutch, as disclosed in Japanese Published Unexamined Patent Application No. 60/36946.
In recent years, on the other hand, so-called shaftless rotary presses in which different driven components are driven independently by separate drive sources so that synchronous control can be achieved electrically so as to adequately match the rotating speeds and phases of the drive sources and the driven components, as disclosed in Japanese Patent Nos. 3037650 and 3059081, for example, have been widely used because they have various advantages in printing operation.
However, when electrical synchronous control becomes inoperative in the shaftless rotary press during printing operation due to a power failure, for example, drive sources and driven components tend to continue rotation owing to the inertial forces thereof, leading not only to deteriorated printing performance but also to various troubles, such as the breakage of the web due to uneven tension on the web and the resulting unwanted clinging of the broken web around the rotary parts. It takes much time to restore the normal printing operation by removing the clung web and re-threading the web into the traveling path. These time-consuming restoring operations has made it difficult to quickly resume printing even after the restoration of main power supply. As a result, these operational troubles have posed a big problem difficult to solve especially in newspaper printing and other printing jobs requiring speed and timeliness.
As a solution for this problem, on the other hand, means for stopping the rotary press by individually braking driven components of a shaftless rotary press system, as disclosed in Japanese Patent No. 3037650, when power feeding is interrupted due to a main power failure. In this type of rotary-press control, however, there is a difference in the inertial forces of the driven components that keep rotating after power feeding has been interrupted, and accordingly there is no small difference in braking forces to put brake on the rotation caused by the inertial forces. In addition, there is some time lag in the start of braking in each braking section. All these factors have caused variability in the time required for the rotating speed of each driven component begins to decrease due to braking as well as the time required for each driven component comes to a halt. This results in uneven tensions on the traveling paper web in the rotary press, leading to the breakage of the web or the clinging of the web around the rotary parts.
It is an object of the present invention to switch over the operation of a shaftless rotary press in which the components thereof are subjected to electrical synchronous control when power feeding is interrupted due to a failure of main power supply so that a traveling paper web can be braked with a constant braking force to prevent uneven tensions from being exerted on the paper web even when power feeding is discontinued due to a main power failure, thereby, in a breakage of the paper web, preventing the broken web from clinging around the rotary components.
It is another object of the present invention to switch over the operation of a shaftless rotary press in which the components thereof are subjected to electrical synchronous control when power feeding is interrupted due to a failure of main power supply so that a traveling paper web can be braked with a constant braking force that is larger than the braking force before the interruption of power feeding to prevent uneven tensions from being exerted on the paper web even when power feeding is discontinued due to a power failure, thereby, in a breakage of the paper web, preventing the broken web from clinging around the rotary components.
The present invention that can accomplish these objectives makes it possible to resume the printing operation of the shaftless rotary press immediately after the power is restored.
The present invention also accomplishes the control, in a main power failure, of a rotary press that carries out printing operation by driving the printing section and the folding section with separate drive sources, pulling the printing material that is currently being braked in the paper feeding section, and bringing the blanket cylinder of the printing section into contact with the printing material; the control to cope with the power failure being accomplished in such a manner that the braking of the printing material in the paper feeding section is changed over to a braking mode with a constant braking force as soon as power feeding to the rotary press is interrupted in the main power failure, a power failure signal is output by detecting a voltage drop due to the power failure, the power supply is changed over to a battery power supply, the blanket cylinder is detached from the printing material with the battery power upon receipt of the power failure signal, and the printing material pulling mechanism in the folding section is decelerated and brought to an emergency halt within a given length of time also with the battery power upon receipt of the power failure signal.
The present invention accomplishes the control, in a power failure, of a rotary press that carries out printing operation by driving the printing section and the folding section with separate drive sources, pulling the printing material that is currently being braked in the paper feeding section, and bringing the blanket cylinder of the printing section into contact with the printing material; the control to cope with the power failure being accomplished in such a manner that the braking of the printing material in the paper feeding section is changed over to a braking mode with a constant braking force that is greater than the braking force before the power failure as soon as power feeding to the rotary press is interrupted in the power failure, a power failure signal is output by detecting a voltage drop due to the power failure, the power supply is changed over to a battery power supply, the blanket cylinder is detached from the printing material with the battery power upon receipt of the power failure signal, and the printing material pulling mechanism in the folding section is decelerated and brought to an emergency halt within a given length of time interval also with the battery power upon receipt of the power failure signal.
The present invention accomplishes the control, in a power failure, of a rotary press comprising separate drive sources in the printing section and the folding section thereof, a printing material braking mechanism for countering the pulling of the printing material in the paper feeding section thereof, a blanket cylinder moving mechanism for selectively moving the blanket cylinder in a direction away from the direction in which the blanket cylinder comes in contact with the printing material in the printing section thereof, and a printing material pulling mechanism for pulling the printing material by the rotation of a drag roller at least in the most upstream part of the folding section; the improvement comprising a printing material braking mechanism adapted to be changeable to a braking mode with a constant braking force as soon as power feeding to the rotary press is interrupted due to a main power failure, an uninterruptible power supply having a power failure signal output section with the power input side thereof connected to an external power supply for outputting a power failure signal by detecting a voltage drop on the power input side at the power failure and a battery power supply for outputting power to the power output side thereof upon detection of the voltage drop on the power input side at the power failure, a drive source control section provided for each drive source for controlling the rotation of the drive sources in the printing section and the folding section, a rotation control signal output section for outputting a signal for the synchronous control of the rotation of each drive source, and a moving mechanism control section for operating the blanket cylinder moving mechanism to selectively bringing the blanket cylinder into contact with or away from the printing material; at least the drag roller drive source control section, the rotation control signal output section and the moving mechanism control section of the printing material pulling mechanism at least on the most upstream side of the folding section being connected to the power output side of the uninterruptible power supply, and at least the rotation control signal output section and the moving mechanism control section being connected to the power failure signal output section of the uninterruptible power supply, so that the blanket cylinder is detached from the printing material based on the signal from the power failure signal output section, and the printing material pulling mechanism on the most upstream side of the folding section is controlled for deceleration and stop based on the output signal of the rotation control signal output section.
With this construction of the present invention, the following operation is carried out when a power supply failure, such as the interruption of an external power supply, occurs.
First, when the voltage on the power input side of the uninterruptible power supply drops, the power failure signal output section of the uninterruptible power supply outputs a power failure signal, and feeds power to the power output side from the battery power supply. As power feeding is interrupted due to a power failure, such as a failure of an external power supply, the printing material braking mechanism in the paper feeding section is changed over to a state where the braking force is kept constant.
The power failure signal output by the power failure signal output section is input into the rotation control signal output section and the moving mechanism control section. The power output by the battery power supply to the power output side is input into the drag roller drive source control section, the rotation control signal output section and the moving mechanism control section of the printing material pulling mechanism at least on the most upstream side of the folding section.
The rotation control signal output section and the moving mechanism control section are changed over to a rotary press stop mode upon receipt of a power failure signal, and start operation in the rotary press stop mode based on the power fed by the battery power supply. The drag roller drive source control section continues drive source control operation based on the rotary press stop mode signal output by the rotation control signal output section in accordance with the power fed by the battery power supply. That is, the rotation control signal output section outputs a control signal that gradually decelerate and bring to a halt the drag roller of the printing material pulling mechanism on the most upstream side of the folding section, so that the printing material that is traveling in the rotary press is stopped after deceleration with a given length of time.
Upon receipt of this control signal, the drag roller drive source control section decelerates the rotation of the drag roller of the printing material pulling mechanism on the most upstream side of the folder and finally brings it to a halt. The time from deceleration to stop is determined within a time interval in which power can be fed from the battery power supply.
Upon receipt of the power failure signal, the moving mechanism control section immediately actuates the blanket cylinder moving mechanism to move the blanket cylinder from the printing position at which the blanket cylinder comes in contact with the printing material to a non-printing position at which the blanket cylinder is detached from the printing material.
The printing material braking mechanism in the paper feeding section that has been changed over to a constant braking force mode continues braking with a constant braking force the printing material that is being pulled by the drag roller of the printing material pulling mechanism on the most upstream side of the folding section.
As described above, the rotation control signal output section, the drag roller drive source control section, the moving mechanism control section and the printing material braking mechanism are operated so that the printing material traveling in the rotary press is decelerated and brought to a halt by electrical control under the influence of the constant braking force.